1. Technical Field of the Invention
The present invention relates to telecommunications, and more particularly, to wireless data communications.
2. Description of Related Art
Advances in microelectronic technology have provided numerous portable computer-like devices. Portable computer-like devices include, for example, Personal Digital Assistants (PDA), Handheld Personal Computers (HPC), and smart phones.
A PDA is a handheld device which acts like an electronic organizer or diary. Among the functions performed by a PDA include small scale database applications, word processing, and appointment scheduling. A handheld personal computer, often referred to as a xe2x80x9cpalm topxe2x80x9d provides personal computing in a handheld device. A smart phone is a microcontroller-controlled electronic telephone with a touch sensitive screen that interactively allows a user to place a call, send E-mail, and perform certain financial transactions.
Each of the foregoing devices provide a user with computer-like functions. However, in contrast to desktop computers, the foregoing devices are portable, thereby permitting a user to be mobile. Additionally, with advances in cellular telecommunications, the functions of the foregoing devices are expanded to client/server applications as well.
Computer systems are often connected to another computer system, typically a server, to form a computer network. When networked together, communication between the separate computer systems is possible. A server is a class of shared computers that are used to handle service common to all connected computers, known as clients. A common use of the server also includes handling and maintaining databases, and controlling access to voice mail, E-mail, or facsimile. Performing the foregoing functions at a server is advantageous because the same functions can be accessed from any of the clients which can be located about a large geographic area. Additionally, the functions can be simultaneously accessed by more than one client.
Clients often access servers using a wireline connection, such as through the public switched telephone network or a coaxial cable. However, advances in cellular telecommunications technology now allow clients to access servers using the mobile air interface. Because a wireline connection is no longer required, handheld computer-like devices can access server functions without restricting the user""s mobility. A computer, or computer-like device accessing a server using the air interface is known as a wireless client.
When a client/server connection is established, any information to be transmitted must be formatted in a manner suitable for transmission. Additionally, information regarding various transmission parameters, such as the speed, ready to send signals, and ready to receive signals, must also be formatted and transmitted. Furthermore, the format of the information, as well as the convention for communicating the transmission parameters, must be known to the client or server receiving the transmission. The foregoing is accomplished using what is known in the art as a protocol. A protocol is a specific set of rules, procedures or conventions relating to the format and timing of data transmission. By establishing a common protocol between the client and server, information can be transmitted in a reliable manner understandable to both the client and the server.
The Wireless Application Protocol (WAP) was created to optimize data communication with wireless clients. Ideally, the WAP based service should be used on top of a packet switched transport such as Cellular Digital Packet Data (CDPD) or General Packet Radio Service (GPRS). However, due to standardization delays and the prohibitive cost of deploying a new packet radio service, operators are looking at other transports to offer WAP based service.
Another transport that has been considered is direct digital cellular circuit switched data calls (direct digital calls). Unlike conventional data calls which require a latency time for modem synchronization, direct digital calls do not involve any modems and therefore can be easily established and torn down as needed. The foregoing is ideal for many client/server and Internet applications which communicate in transmission bursts.
Applications which communicate in transmission bursts are characterized by very short periods of high data rate transmission, followed by longer periods of inactivity. Transmission in bursts is advantageous because the communication channel need only be maintained during the very short periods of transmission and can be torn down during the longer periods of inactivity.
The greatest limitation for using direct digital calls for a WAP based application is the fact that direct digital calls can only be used when the client originates the call to the server. The foregoing limitation is known in the art as an information pull model. The information pull model is a significant limitation for notification service applications, such as E-mail, stock price alert, and security alert, to name a few, where it is desirable for the server to notify the client of a particular event in a real-time fashion. A system where a server initiates a communication to the client and forwards information is known in the art as an information push model.
Accordingly, it would be advantageous if the server is able to push information to a wireless client in a direct digital call environment.
The present invention is directed to a system, method, and apparatus for transmitting a digital data communication from a server to a wireless client, wherein the server initiates a call to push information to the client. A wireless application protocol gateway is interfaced by means of a signal link to a home location register of a cellular telecommunications system. The signal link permits the WAP Gateway to query the home location register for routing information needed to deliver a call with push information to the wireless client using the infrastructure of the cellular telecommunications system.
The present invention is also directed to a wireless application protocol gateway for routing a digital data communication from a server to a wireless client, wherein the server initiates a call to the client. The wireless application protocol gateway maintains a table that correlates Internet Protocol (IP) addresses with Mobile Services Integrated Services Digital Network (MSISDN) numbers or Mobile Identification Numbers (MIN) of the wireless clients. When the wireless application protocol gateway receives a digital data communication addressed to a particular IP address, the wireless application protocol gateway determines the corresponding MSISDN number of the wireless client. The MSISDN number can then be used to initiate an incoming call to the wireless client using the infrastructure of the cellular radio system.
The present invention is also directed to a method for transmitting a digital data communication from a server to a wireless client, wherein the server initiates an incoming call to the client. When a digital data communication is received at a wireless application protocol gateway, the wireless application gateway queries a database storing location information for the wireless client. In response to the query, a dynamic IP address is allocated to the wireless client and transmitted to the wireless application protocol gateway. The wireless application protocol gateway then transmits the digital data communication using the dynamic IP address as a destination address.